Swift：如何从Dictionary中删除空值？ [英] Swift: How to remove a null value from Dictionary?

问题描述

我是Swift的新手，我在从JSON文件中过滤NULL值并将其设置为Dictionary时遇到问题。
我从服务器获得空值的JSON响应，它崩溃了我的应用程序。

I'm new in Swift and I have a problem with filtering NULL values from JSON file and setting it into Dictionary. I getting JSON response from the server with null values and it crashes my app.

以下是JSON回复：

"FirstName": "Anvar",
"LastName": "Azizov",
"Website": null,
"About": null,

我将非常感谢您提供帮助以解决问题。

I will be very appreciated for help to deal with it.

UPD1： At这一刻我决定以下一种方式做到这一点：

UPD1: At this moment I decided to do it in a next way:

if let jsonResult = responseObject as? [String: AnyObject] {                    
    var jsonCleanDictionary = [String: AnyObject]()

    for (key, value) in enumerate(jsonResult) {
      if !(value.1 is NSNull) {
         jsonCleanDictionary[value.0] = value.1
      }
    }
}

推荐答案

您可以创建一个包含相应值为零的键的数组：

You can create an array containing the keys whose corresponding values are nil:

let keysToRemove = dict.keys.array.filter { dict[$0]! == nil }

然后循环遍历该数组的所有元素并从字典中删除键：

and next loop through all elements of that array and remove the keys from the dictionary:

for key in keysToRemove {
    dict.removeValueForKey(key)
}

---

更新2017.01.17

力量展开算子有点难看，虽然安全，但正如评论中所解释的那样。可能有其他几种方法可以实现相同的结果，相同方法的更好看方式是：

The force unwrapping operator is a bit ugly, although safe, as explained in the comments. There are probably several other ways to achieve the same result, a better-looking way of the same method is:

let keysToRemove = dict.keys.filter {
  guard let value = dict[$0] else { return false }
  return value == nil
}

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